Method for producing antenna components
A method for producing internal antenna components for small radio devices. A radiator is supported by a flat-topped protrusion formed in a plastic blank—e.g., by pressing with a hot tool. The length of the protrusion sets the height of the planar antenna. The radiator and its conductors are formed by removing material from a conducting film attached to the top of the protrusion. A feed and a shorting conductor are formed as extensions of the radiator. Contacts are attached to the feed and the shorting conductor to connect the antenna component to the radio device. Elongated gaps made in the plastic blank around the edges of the protrusion can facilitate loosening of the component. A plurality of antenna components can be formed on a uniform plastic blank and placed in a common package. The method results in low manufacturing costs and quick production time.
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The invention relates to a method for producing components suitable for internal radiators, particularly in small-sized radio devices.
A growing number of different mobile phones and other small-sized radio devices are on the market for different telecommunication needs and for customers with different solvency. Regarding the price it is of course desirable that the device assortment extends as low as possible. The price of a device depends mainly on its manufacturing costs, which therefore must be forced low, particularly in cheap models.
This description depicts one possibility to reduce the manufacturing costs of a radio device, regarding the antenna. In practice the antennas located in small-sized radio devices have a planar structure: The antenna comprises a radiating plane and a ground plane in parallel with it. For instance in mobile phones a common way to make a planar antenna is that a dielectric support frame is formed by injection molding, and the radiating plane with its feeding and shorting conductors is made of metal sheet by cutting and bending. The support frame and the radiating plane are fastened to each other, and the resulting component is attached to a circuit board with the ground plane on its surface. Disadvantages of the method are the high costs required by the production line and the relatively long throughput time in the production. A simpler method is for instance to utilise printed circuit board techniques: a larger number of mutually identical radiator patterns are formed on a surface of a relatively large circuit board, and then the board is cut into pieces. Then the individual radiators are relatively cheap, as are their support mechanisms. However, the assembly of the antenna with its feeding and shorting conductors causes significantly high costs.
Usually a radio device as a whole is produced in a different place than its antenna component. In that case, by using known antenna manufacturing methods the antenna components are then packed one by one for the transport, which causes a significant extra cost.
SUMMARY OF THE INVENTIONThe object of the invention is to reduce said disadvantages relating to prior art. The method according to the invention is characterised in what is presented in the independent claim 1. Some preferred embodiments of the invention are presented in the dependent claims.
The basic idea of the invention is as follows: In order to support a radiating planar element, or a radiator, a protrusion is formed on a planar plastic blank, for instance by pressing with a hot tool. The height of the protrusion is the designed height of the planar antenna. The actual antenna with its conductors is formed by removing material from a conducting film, which is on the plastic blank, or attached to the top of the protrusion. The feeding conductor and the shorting conductor of the antenna are formed as extensions of the radiator and located on a surface of the protrusion. Both to the feeding and to the shorting conductors is attached a contact in order to connect the antenna component later to a radio device. Elongated gaps can be formed at the edges of the protrusion, in the plane of the plastic blank, in order to facilitate the loosening of the component. A plurality of antenna components is formed on a uniform plastic blank, whereby the components can be finally placed in a common package.
An advantage of the invention is that the manufacturing costs of a single antenna are low compared to prior art. This is due to the fact that the shaping of the plastic plane mentioned above is cheap compared to injection moulding, and to the fact that the mass production of the antenna components and their installation in the final product are carried out in an easier manner. A further advantage of the invention is that the throughput time of the antenna components in the production is relatively short. A further advantage of the invention is that it is not necessary to pack the antenna components one by one, but a relatively large amount can be packed in one operation.
The invention is described in detail below. In the description reference is made to the enclosed drawings, in which:
The protrusions, acting as support for the radiator, can be made also by a deep drawing technique, instead of pressing by a hot pushing head. An alternative to the attachment of a finished radiator is that the whole plastic blank is first coated with a conductive film, on which a radiator pattern and the feeding and shorting conductors are machined before making the protrusion. In this case it is no more necessary to attach the radiator, of course. However, the conductive film must be left unfastened to the plastic blank at that strip where the feeding and shorting conductors will be located, and these are finally fastened to the sides of the protrusions.
Further the antenna component 400 comprises contacts in order to connect it electrically to the final product. In this example the contacts are of the spring type. The first spring contact CT1 is connected fixedly to the antenna's feeding conductor FC, and the second spring contact CT2 is fastened to the shorting conductor SC. The connections are made for instance by spot welding. The free ends of both contacts are bent below the antenna component. When the component is mounted in a radio device the first spring contact CT1 will be connected to the antenna port of the radio device and the second spring contact CT2 will be connected to the antenna's ground plane. This provides an antenna of the PIFA type (Planar Inverted F-Antenna). For the mechanical attachment of the antenna component an attachment hole AH is visible in the flange-like lower edge of the support part.
Above is described a method according to the invention. The invention is not limited just to the cases described above. The order of the operations can vary to some degree, and concerning for instance the embodiments of
Claims
1. A method for producing antenna components for a planar antenna, the method comprising:
- forming an antenna radiator, feed conductor and shorting conductor on a uniform conducting layer;
- machining a protrusion into a planar plastic blank to create a dielectric supporting part, wherein the protrusion has a height which is a designed height of the planar antenna;
- fastening the formed radiator, feed conductor and shorting conductor to the protrusion;
- providing at least one opening in the planar plastic blank around said protrusion for the attachment of contacts for connecting the antenna component to a radio device; and
- attaching a contact, respectively, to the feed conductor and to the shorting conductor.
2. The method according to claim 1, wherein the plastic blank is a tape wound on a coil former, and further including the step of processing a plurality of antenna components in successive locations on the tape while the tape is unwound from said coil former.
3. The method according to claim 2, further including the step of winding said tape on a second coil former after the processing step.
4. The method according to claim 2, further including the step of cutting said tape into fixed-length pieces after the processing step.
5. The method according to claim 1, wherein the plastic blank is a plate, and further including the step of processing a plurality of antenna components row by row into the plate.
6. The method according to claim 1, wherein the machining step is performed by a hot tool.
7. The method according to claim 1, wherein the machining step is performed by a deep drawing technique.
8. The method according to claim 1, wherein the fastening step fastens the formed radiator, feed conductor and shorting conductor to an outer surface of said protrusion.
9. The method according to claim 1, wherein the fastening step fastens the formed radiator, feed conductor and shorting conductor to an inner surface of said protrusion.
10. The method according to claim 1, wherein said protrusion is flat-topped.
11. The method according to claim 1, wherein said conductors and radiator are attached by gluing.
12. The method according to claim 1, wherein said conductors and radiator are attached by a self-adhesive joint.
13. The method according to claim 1, further including the step of welding said contacts to the radio device.
14. The method according to claim 1, further comprising the step of forming openings in the planar plastic blank around said protrusion in order to facilitate removal of the antenna component from the plastic blank.
15. A method for producing antenna components for a planar antenna, the method comprising:
- providing a planar plastic blank having first and second surfaces and including a conductive film attached to the first surface;
- machining a protrusion into the planar plastic blank to create a dielectric supporting part, wherein the protrusion has a height which is a designed height of the planar antenna;
- forming an antenna radiator, feed conductor and shorting conductor by removal of a portion of the uniform conducting layer on the protrusion;
- providing at least one opening in the planar plastic blank around said protrusion for the attachment of contacts for connecting the antenna component to a radio device; and
- attaching a contact, respectively, to the feed conductor and to the shorting conductor.
16. The method according to claim 15, wherein the plastic blank is a tape wound on a coil former, and further including the step of processing a plurality of antenna components in successive locations on the tape while the tape is unwound from said coil former.
17. The method according to claim 16, further including the step of winding said tape on a second coil former after the processing step.
18. The method according to claim 15, wherein the plastic blank is a plate, and further including the step of processing a plurality of antenna components row by row into the plate.
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Type: Grant
Filed: Mar 8, 2004
Date of Patent: Jul 3, 2007
Patent Publication Number: 20040244187
Assignee: Pulse Finland Oy (Kempele)
Inventors: Petteri Annamaa (Oulunsalo), Kimmo Antila (Kiviniemi), Ilkka Niemla (Oulu), Heikki Riekki (Oulu)
Primary Examiner: Minh Trinh
Attorney: Darby & Darby
Application Number: 10/800,081
International Classification: H01P 11/00 (20060101);